Mobile drafting apparatus



Sept. 3, 1957 c. E. Jus-ns 2,804,691

A MOBILE DRAFTING APPARATUS Filed Aug. l5, 1,955 3 Sheets-Sheet l 35 33 INVENTOR n Charles E'. Jus 91s,

A TTORNEY.

c. E. Jus'rls MOBILE DRAFTING APPARATUS Sept. 3, 1957 5 Sheets-Sheet 2 Filed Aug. 15, 1953 INVENToR. 77a fles E'. Jz'lsl'a,

ATTORNEY.

Sept. 3, 1957 QE. Jus-ns l MOBILE DRAFTING APPARATUS 3 Sheets-Sheet 5 Filed Aug. 13, 1953 l fu-l JNVENTOR. U |||ll| 47 C/irles E. Jasizs,

' www ATTORNEY.

nited States arent nice MOBILE DRAFTEJG APPARATUS Charles Eugene `lustis, Jenkintown, Pa.. Application August 13, 1953, Serial No. 374,072

1 Claim. (ci. .a3-s0) 'This invention has general reference to mobile drafting apparatus and, more particularly, to the species or type involving a straight-edge with associated tractable means whereby said straight-edge may be moved, relative to the working surface of a drafting board, for the purpose of drawing parallel lines in horizontal, or otherwise desired, spacial parallelism.

Such mobile drafting apparatus, as heretofore designed, have generally involved the employment of a iiexible wire or twine trained about a series of pulleys, or analogous means, mounted to the drawing board; but such means have proven, in practice, unsatisfactory and inevitably develop irregularities in movement of the straight edge, due to stretch or shrinkage of said wire or twine.

Another disadvantage inhering to previous mobile drafting apparatus, of the species above referred to, is due to their complicated make-up and construction, as well as 5 being diiiicult to install with the needful accuracy.

Accordingly, my invention has for its primary object to provide an operatively effective mobile drafting apparatus, of the above indicated species, characterized by refinements that ensure positive action, with freedom from developing irregularities during usage.

Another object of my invention is to provide a mobile drafting apparatus, of the foregoing indicated type, including a novel form of straight-edge that is of a design and cross-section highly resistive to the development of frictional restraint, incidental to movement over the paper, or tracing cloth on which the drawing is produced.

A further object of my invention is to provide a mobile drafting apparatus of the species above indicated, which is simple to construct, comparatively cheap to manufacture, and appreciably smoother in action than the generality of such previously known apparatus.

Other objects with ancillary advantages, will hereinafter appear as the nature of my invention is more particularly described; while said invention essentially consists in the novel structural features and combinations of parts, illustrated by the accompanying three sheets of drawings, and the novelty whereof is more specifically defined in the claim.

In the drawings:

Fig. l, Sheet l, is a perspective view of a conventional drawing-board equipped with a typical embodiment of the novel straight-edge, and an associated direct-acting mobile means for operating said straight-edge.

Fig. 2 is a detail section, taken approximately on the plane designated by the angled-arrows lI-II in Fig. l; but drawn to a larger scale for purposes of clarity.

Fig. 3 is a cross-section taken on the plane indicated by the angled-arrows III-lil in Fig. 2, but drawn to a relatively exaggerated scale for the clearer showing of important details.

`Fig. 4 is a fragmentary perspective view, mainly in vertical'section, of a portion of the novel straight-edge and associated direct-acting mobile mechanism.

Fig. 5 is a perspective view, somewhat similar to Fig. 1 of an evenly-tensioned single-cable or modified form Patented Sept. 3, 1957 of my invention, which is hereinafter fully described, and more particularly adapted for attachment to a conven tional drawing-board, by the user thereof, within the marginal confines of such board.

Fig. 5a is a line diagram of the single-cable means shown in Fig. 5 and hereinafter fully described.

Fig. 6 is a cross-section taken on the plane indicated by the angled-arrows VI-VI in Fig. 5, but drawn to a larger scale for better illustration of important details of the straight edge.

Fig. 7 is a fragmentary perspective view of one end portion of the straight-edge, taken as typically indicated by the bracket VII, at the right-hand side of Fig. 5, but drawn to an enlarged scale for clarity in illustration.

Fig. 8 is a perspective view of a tandem, evenlytensioned, cable-means, of my invention, along the lines of Fig. 5, and in which the straight-edge is lengthwise hollowed-out for passage therethrough, with lateral guidance for an intermediate portion of the said cable-means.

Fig. 8a is a line diagram of the tandem cable means shown in Fig. 8 and hereinafter fully explained.

Fig 9 is an enlarged-scale cross-section taken on the plane lX-IX of Fig. 8, as viewed in the direction of the respectively-associated angled-portions of said arrows; and

Fig. 10 is a fragmentary perspective view of an outer end portion of the straight-edge, as designated by the bracket X at the right-hand of Fig. 8.

1n the drawings aforesaid, like characters of reference are applied to corresponding parts in all the views and, in the following descriptive matter, specific terms are employed for the sake of brevity. However, it is to be understood the scope of my invention is not thereby limited, as each such term is intended to embrace all equivalents which perform the same function for an analogous purpose.

Referring generally to the accompanying drawings; the reference character 11 comprehensively designates a conventional drawing-board, and, primarily to Figs. 1-4, it will be observed said board 11 is equipped, proximate the left-and-right hand side edges 12, 13 respectively, with comparatively narrow rigid toothed-rack components 14, 15. The rack component 14 is conveniently, although not essentially, securely attached to the board 11 as by clamp screws 16; whereas the right-hand rack-component 15 is provided with elongate slots 17 for passage of clamp screws 16, in order that the teeth 18 of both rack components 14, 15 may be accurately set and firmly secured in directly aligned spaced registrationyfor a purpose hereinafter further referred to.

A sheet of drawing paper 19 is shown in Figs. l, 5 and 8, more particularly, as applied to the drawing board 11y by aid of conventional thumb-tacks 20; while 21 indicates a building floor-plan, for instance, as being drawn thereon; although it will be readily understood any other right-lined image can be drawn thereon. r

Turning now to the straight-edge 22 of Figs. 1 4, more particularly, the same is preferably made of transparentV plastic, and conveniently of the cross-section best understood from Figs. 2 4. ln other words the straight-edge 22 is of blade or strip formation to embody parallel edges' 23, 23, with an intermediate and medially lengthwise stiffener or body-portion 24.

bodyportion 24 embodies opposingly-inclined spaced-ribs l 26 having rounded-edges 27, that afford grippage when moving the straight-edge 22 (up and down) verticallyjof the drawing paper, or the like 19. Additionally, it is to The body-portion 24,'it is to be particularly remarked, is provided with relatively-` be remarked that the respective straight-edge rib roundededges 27 merge with relatively-reduced parallel ats 28, slightly-inclined outwards and downwardly, relative to the horizontal, and stepped down at 29 to provide fianking sections 30 tapering to v'the straightledge parallel edges 23 hereinblefore referred to. The under face of the straightedge 22, it is tobeparticularly noted is Slightly concaved, transversely, as indicated at 31, Figs. 2, 6, 7, 9 and l0, so that the parallel-edges 23, 23 thereof make line contact on the drawing paper 19 only;'whereby the frictional Contact of the parts 19 and 22 is reduced to a minimum; while rthe operational movement of the part 22 is raised to an optimum, due to the practical elimination of frictional resistivity developing between said Vparts 1,9 and 22. It is, also, to be noted Vthat the grippage-ribs 26, 26, define therebetween 'a troughing or rest 22 for temporary retention of pencils, pens, and other articles commonly used by draftsinen, without slippage of said items onto the drawing paper 19 and rolling from-off the board lll Referring now tov the rectangular downwardly-open pockets 25 in the straight-edge 22, it will be observed that they, respectively, afford snug inset-housing for an inverted channel-section hanger-device 32, in turn providing journal bearing, by aid of spaced spindles 33, for duplex tooth-gears or pinions 34 with associated antiflriction material spaced washers or guide anges 35 for co-ac'tion with theregistering toothed-rack 14 or 15, in an obvious manner.v It will be, of course, understood that the teeth 18` of the respective rack components 14, 15 and pinions 34 are complemental to ensure positive and smooth operation of the straight-edge 22. It is likewise to be observed, that the hanger devices 32 are rigidly secured in the'respective pockets 25 by aid of an inset transverse clamp-plate 36, preferably intermediate the duplex pinions 34, and associated hold-fast elements or rivets 37. Furthermore, it is to be particularly noted that, by use of the spaced duplex-pinions 34, the straight-edge 22 is at all times positively maintained in balance, or kept in parallelism withrespect to the rack components 14, 15; and thereby restrained against any lateral rocking motion.

' Turning now to the modified form of my invention illustrated in Figsf-7, inclusive, all parts corresponding with those previously described are indicated by like reference characters, to obviate unnecessary repetitive explanation and, accordingly, only those items which characterize this form or type of myinvention will now be particularly set forth'. In the first place, it is to be observed that the straight-edge 22 corresponds with the one previously explained, excepting that it is comparatively of lighter weight and smaller cross-section; whereas the rack-and-pinion means 14, and 34, for motivating the straight-edge 22 relativeto the drawing-board 11, is substituted by an equally-tensioned single-'strand element 33 and associated anchorages 39, 39 fixed guide-points 40 and tractabledevices 41. The tractable-devices 41 are, preferably, rigidly attached to th'efs'tepp'ed,l or shouldered ends 42 of the straight-'edge'body-portion 24, as by rivets 43 or the like, see Figs. 5 and 7 to best advantage. It is, also, to be particularly remarked, that each tractable-device 41, is preferably in the form of a plate including vertical studs or pins 44 affording journal-bearing for horizontally-rotative circumferentially-grooved pulleys or spools 45. Attention is further drawn to the fact that the stationary guide-points 40, above referred to, are provided with similar circumferentially-grooved small spools 46; also that the concavity ofthe groove47 around the respective spools 45 and 46 is critical, or of a curvature that they normally tend to jointly maintain the strand element 38Acentrally thereof, whereby frictional development therebetween, during operation of my invention, is reduced to zero, for all practical purposes.

Referring now to the placement or winding of the single-strand element 38, and -assuming a start be madeV at theyleft-hand anchorage 39, and by noting theY associatedidirection-indic'ating arrows A, Fig. 5a, thatfsaidVele-rL ment 31 is coiled once about the left-hand lower spool 45 with a clockwise turn, then drawn up and similarly coiled about the upper left-hand spool 45. From the just mentioned spool 45 the strand element 38 is next passed partially about the upper left-hand guide-point 46, and correspondingly on to the right-hand guide-point spool 46; whereupon the strand element 38 passes down to the upper right-hand tractable-device spool 45 and coiled once about the latter with a righthand turn; whereupon it is similarly passed around the associated lower spool 45 and, from the last-mentioned spool 45 it is brought to and secured by the right-hand anchorage 39'. From this explanation, and due to the evenly-tensioned character of the strandelement 38 it will be clearly understood that the tractability of the straight-edge 22, as a mobile unit, is positively attained; as the turns and bends effected therein, in the aggregate, conduce to the definite removal of any possibility of frictional grippage developing.

Referring now to Figs. 8, 9 and 10, which show what I preferably have, for the purpose of differentiation termed a tandem, or further modified, form of my invention, along the lines of that illustrated by Figs. 5-7, inclusive, and wherein like parts, to those previously set forth, are hereinafter designated by corresponding characters of reference in order to dispense with unnecessary repetitive descriptive matter. Firstly, it is to be observed that the straight-edge body-portion 24 is provided with a longitudinal-bore 48 conveniently, although not essentially, of rectangular cross-section, as best shown in Figs. 9 and 10. In other words, the bore 48 is preferably of cornparatively shallow depth relative to its width for a purpose later on herein again referred to. In addition it is to be particularly noted, that the equally-tensioned strand element 38', in this form of my invention, is of greater length than that used in connection with the species shown by Figs. 5-7 inclusive, also that said strand 38 is divided,

and firmly held or secured, medially of its length by means of a suitable clamp-device 49, Fig. 8 only, for reverse placement or directional-guidance. In other words, it is to be understood that the form of my invention, now being described, differs from that shown by Figs. 5 to 7, mainly in the provision of the straight-edge 22" with the longitudinal bore 48; and the use of a stationary or fixed clamp-device 49 for the purpose of dividing the substantially-longer strand element into relatively opposing equal tractive sections 38 which jointly serve to effectively and positively balance the movement of the straight-edge 22". It is also to be remarked, and as better understood by aid of the diagram, Fig. 8a that the strand-element 38', starts at the anchorage 39 and is given a right-hand turn around the left-hand lower guide-spool 45', and then passed through the straightedge longitudinal-bore48, whereupon it is given a counterclockwise turn about the upper right-hand guide-spool 45'; and from said upper spool 45' such strand-element 38f is passed to the stationary guide-point 46' and on to securement by the clamp-device 49, Figs. 8 and 8a. The.

free-portion of the strand-element 38' is thereupon passed to, and partially-trained about the left-hand guide-point 4 6 and downwardly to theupper guide-spool 45'; thence through the straight-edge bore 48 to the lower right-hand guide-spool 45', around which it is given a single righthand turn and.led to the right-hand anchorage 39' where it is secured, as previously explained in connection with Figs. 5-7.

From the foregoing description it is felt that the manner` of operating the straight-edge 22 or 22" will be selfevident, or well understood by any draftsman in that it is movedA up or down relative to the board 11 in accordance with prevailing practice. It will, however, be equally well appreciated that either of the species shown by Figs. 1-4, Figs. 5-7 and Figs. 8-10; are smoothly operable with a minimum of effort incidental tothe elimination of all factors that, heretofore, tended to develop frictienal 'resietaneef It is alsoto be noted that byprovidingz 5 one of the rack-components 15, as shown in Fig. 1, with means enabling its lengthwise adjustment of the items 16, 17, the racks 14, 15 can be readily set and locked with their teeth 18 in yaccurate registration, and so maintained during usage of the straight-edge 22. Also it is to be noted that in the modification, shown by Figs. 8-10, the intersection of the strand-element portions 38 tends to greatly enhance the well balanced operational eiectiveness of the related species or form of my invention.

In the hereinbefore set forth description of the straight edge structure it is stated that the oppositely inclined spaced ribs 26 of Figs. 1 and 6 afford a grippage for effectively moving the straight edge over the drawing paper or drawing surface and also that these ribs define a troughing between them for the temporary retention of pencils, pens, etc. In addition to this novel construction, it will be observed upon reference to the several gures of the drawing that the over-all width of the straight edge is materially greater than the over-all width of the longitudinally extending central portion referred to as the lengthwise stiiener or body portion 24. Consequently it will be seen that by reason of this difference in the relative width of the stiftener and of the straight edge as an entirety, there is provided the advantage that the user of the device can very effectively grip the ribs 26 and firmly holdV the straight edge against movement while drawing a marking implement along the entire length of either of the parallel edges 23. 1n other words, this location of the gripping ribs a substantial distance inwardly from the edges 23 enables the user to draw lines without interference from the fingers holding the straight edge in position by gripping the ribs 26.

It will, of course, be recognized that while reference in the foregoing paragraph has been made specifically to the ribs 26, the same advantages accrue from the construction `of the ribs 26 forming a part of the stiffener or body portion 24 of the structure shown in Figs. 8 to l0.

From the foregoing, it will be clearly apparent that by my present invention there is provided a simple, ecient and very satisfactory mobile drafting means or apparatus which is comparatively cheap to manufacture, easy to use, and furthermore effects a considerable saving of time; while being easy to install, and use; and which is immune against derangement when in service.

Changes in, or modifications of the embodiments of' my invention may occur to those skilled in the art without departure from the practical concept of the present invention; accordingly, to determine its scope reference is directed to the following claim. I, therefore, do not wish to be limited to the exact constructions illustrated and described, but aim to cover by the terms of said claim all those alterations and modifications which rightly come within the scope and purview of the following claim.

I claim:

A straight-edge for a drafting apparatus of the character described, said straight-edge comprising an elongate one piece unitary body of substantial over-all width and having a bottom portion with a transversely arched bottom side and a medial lengthwise stiffening portion upon the top side, said stiifening portion being over-all of a width materially less than the bottom portion and said bottom portion extending at the ends beyond the ends of the stiffening portion and the extended ends having substantially flat top shoulder surfaces, said stiiening portion being formed with upwardly diverging longitudinal linger gripping ribs forming an intervening trough, the over-all width of said stiening portion being materially less than that of the bottom portion whereby said gripping ribs lie a substantial distance inwardly from the longitudinal edges of the bottom portion, and a pair of peripherally grooved spools supported upon and spaced transversely of each shoulder surface for horizontal rotation and lying within the space defined by the width of the stifening portion.

References Cited in the le of this patent UNITED STATES PATENTS 405,217 Lockwood lune l1, 1889 407,144 Wright Iuly 16, 1889 714,594 Marx Nov. 25, 1902 2,100,114 Walsh Nov. 23, 1937 2,234,467 De Lisle Mar. 11, 1941 2,275,251 De Lisle Mar. 3, 1942 2,488,284 Froelich Nov. 15, 1949 FOREIGN PATENTS 164,866 Switzerland Jan. 2, 1934 422,055 Italy `Tan. 9, 1947 

